Flexible diaphragm device



D. W. LLOYD July 24, 1934. 1,967,314

FLEXIBLE DIAPHRAGM DEVICE Filed Feb. 4, 1932 Fign iNVENTOR.

DAVID W. LLOYD A TT ORNE Y.

, ture under pressure.

Patented July 24, 1934 1,967,314] FLEXIBLE DIAPHRAGM DEVICE David W.Lloyd, Clayton, Ma, assignor to. The Westinghouse Air Brake Company,Wilmerding, Pa., a corporation of Pennsylvania Application February 4,1932, Serial No. 590,910

2 Claims.

This invention relates to movable abutments for fluid pressureequipment, and more particularly to that type of abutment whichcomprises a flexible diaphragm and a follower which is adapted to beactuated by thediaphragm.

With the ordinary flexible diaphragm type of movable abutment, it hasbeen found that under usual operating conditions, certain portions ofthe flexible diaphragm engage the guide surface of the plunger formingan integral part of the follower, and that due to such engagements, thediaphragm is chafed and soon weakened to such an extent that it isliable to buckle or rup- Another objection to the diaphragm engaging thesurface of the plunger is that it interferes with the free traverse ofthe follower.

, An object of the invention is to provide means for preventing theflexible diaphragm of a mov- 1 able abutment, engaging the guide surfaceof a follower or plunger carried by the diaphragm.

Another object of the invention is to provide a movable abutmentstructure and aguide therefor, which constitutes a support for thediaphragm and which prevents distortion or collapse thereof when thediaphragm is subjected to fluid pressure.

These and other objects of the invention that will be made apparentthroughout the further description thereof are attained by means of themovable abutment structure hereinafter described and illustrated in theaccompanying drawing; wherein Fig. l is a sectional View of a deviceembodying the invention, the movable abutment being shown in theposition it occupies when subjected to fluid pressure sufiicient toovercome a retracting spring; and

Fig. 2 is a sectional view of a fragment of the 'device shown in Fig. 1,the movable abutment being shown in the retracted position to which itis moved by a spring.

Referring to the drawing, the movable abuts ment is disclosed as appliedto a fluid pressure T device, wherein the movable abutment which may beoperatively connected to a valve device (not shown), and which is movedin one direction by fluid pressure against the opposing force of aspring, is moved in the opposite direction by l the spring when thepressure, is relieved.

V The equipment comprises, for example, a casing 3, defining a chamber 4to which fluid under pressure is adapted to be supplied, and which isclosed by a movable abutment comprising a flexible diaphragm 5 having arelatively deep anthe position shown in nular corrugation 6 forpermitting relatively long travel of the follower or plunger 7 that isclamped to the central portion of the diaphragm by a v threaded disc ornut 8. The diaphragm is clamped between the end flange 9 of the casing 3and a cap 11, which is secured to the casing by clamp bolts (not shown)in the usual manner, so as to provide a fluid tight seal between thechamber 4 and the atmosphere.

The follower or plunger '7 is provided with an integral valve operatingstem 12, that may be connected to a slide or disc valve or to valveoperating linkage (not shown) .as preferred. The follower is alsoprovided with an integral guide portion 13. The cap 11 is provided witha bore 14 in which the plunger 13 is slidably mounted, and the chamber15 at the upper face of the plunger may be open to the atmospherethrough a passage 16.

A spring 17, centered between the cap 11 and 75 the plunger 7 by a lug18 in the cap, and a recess 19 in the plunger 7, urges the abutment fromFig. 1 toward the position shown in Fig. 2.

In the usual abutment structure of the type described and having aflexible diaphragm with a deep corrugation, there is a tendency of thefluid pressure in the chamber 4 to force a wall 21 of the corrugationinto contact with the guide surface 10 as the plunger is being movedinto the bore 14, thereby subjecting it to a chafing action. Such actioneventually wears the diaphragm and causes rupture thereof and alsoprevents free movement of the movable abutment, and is, therefore,undesirable.

In the improved structure, the inner face of the cap 11 is provided withan annular groove 22 conforming in contour with the outer surface of thecorrugation 6 of the diaphragm as indicated in Fig. 1, and which fullysupports the diaphragm and determines its contour when the diaphragm issubjected to sufficient pressure to compress the spring 1'? and permitmovement of the plunger 7 to the position shown in Fig. l. Distortion orcollapse of the diaphragm is therefore prevented.

The annular groove 22 provides an annular head or rim 23, that isengaged by the wall 21 of the corrugation when the diaphragm issubjected to pressure and occupies the position shown 5 in Fig. 1, andserves to hold the corrugation of the diaphragm out of contact with theplunger. Chafing and consequent destruction of the diaphragm istherefore prevented by the provision of the annular bead or rim 23.

While I have disclosed the invention as applied to a fluid pressuredevice for operating a valve equipment, it is obvious that the inventionis applicable to a variety of movable abutment structures employingdiaphragms and that changes may be made in the construction withoutdeparting from the spirit of the invention.

Having now described my invention, what I claim. as new and desire tosecure by Letters Patent, is:

1. In a fluid pressure device, a casing and a cover therefore, having aguide way and a corrugated flexible diaphragm clamped between the casingand the cover and having a plunger provided with a guide engagingportion movable with respect to the guide Way, the said cover having anannular groove adjacent the guide way for receiving the corrugation andsupporting it out of contact with the guide engaging portion of theplunger.

2. In a fluid pressure device, the combination with a casing having aguideway, and a plunger provided with a guide portion and movable intothe guideway, of a flexible diaphragm having a relatively deepcorrugation and supported at its periphery by the casing and attached atits central portion to said plunger and adapted to be in foldedcondition when the plunger is in its inner position Within the guideway,the said casing having an annular groove adjacent the guideway forreceiving the corrugation when the free portion of the diaphragm is infolded condition for supporting the corrugation out of engagement withthe guide portion of the plunger.

DAVID W. LLOYD.

